Translation of PCT/EP00/01295 as filed on Feb. 17, 2000
The invention concerns a cleaning element, in particular for cleaning teeth, and a method of producing this cleaning element.
Science has proved that cleaning of the interdental spaces is particularly important for keeping teeth, and especially the tooth supporting tissue, healthy, since gum diseases and diseases of tooth supporting tissue, so-called paradontitis, usually originate in the interdental spaces. A major cause of such diseases is insufficient cleaning of the interdental spaces which may even result in bone degeneration. Satisfactory cleaning of the interdental spaces using manual or electric tooth brushes is not possible, since only approximately ⅗ of all tooth surfaces can be reached for cleaning with a toothbrush. Special cleaning devices must therefore be used.
Interdental cleaning means in the form of interdental brushes or toothpicks are often used for cleaning the interdental spaces, wherein the latter are used in particular for cleaning the easily accessible interdental space between bridge ends and in the sulcus region. Various embodiments of conventional toothpicks are made from differing materials and have differing surface configurations. The main disadvantage of a toothpick is that it contacts and treats the surfaces of the teeth in the interdental area in a merely tangential or point-like manner and cleaning of the entire surface of the tooth is not possible.
In addition to the toothpicks mentioned, cleaning threads, i.e. dental floss, have also been used for some time which are introduced into the interdental spaces and pulled over the surface of the teeth. Although dental floss can be used to clean plaque from locations which are inaccessible with brushes, and although dental floss is acknowledged by dentists to be the best cleaning method, it has not gained a sufficient degree of acceptance with the general public. One reason therefor is that handling of the dental floss is considered to be complicated by the untrained user and initial improper use often leads to painful injuries, e.g. with the dental floss cutting into the gums.
Dental floss usually consists of a thread-like endless carrier which may be a monofile, a multifile, a thread or a tape, etc. The endless carrier may be waxed and, optionally, fluoridated. Most of the dental floss available on the market is completely or at least partially enclosed along its length with a flock by applying a glue layer onto the endless carrier into which microfibers or microbristles are embedded. However, it has turned out that the polymer fibers forming the flock are not fixed on the endless carrier in an abrasion-proof manner and may become detached during use causing discomfort to the users. Moreover, scientific studies prove that the detached fibers are damaging to the health should they enter into the body. In order to avoid these disadvantages, one has attempted to develop sliding, nonfraying dental floss. However, when the dental floss slides across the tooth surfaces, it does not effect a brushing action and only a limited amount of cleaning can be achieved. To prevent the dental floss from cutting into the gums (or to at least reduce this danger), the dental floss would have to have a larger diameter. This would, however, make the dental floss excessively thick and it could no longer be introduced into all interdental spaces.
It is the underlying purpose of the invention to create a cleaning element, in particular for cleaning teeth, of the mentioned kind which ensures reliable and gentle cleaning of the tooth surfaces. Moreover, a method should be created for manufacturing the cleaning element quickly and inexpensively.
With regard to the cleaning element, the above-mentioned objective is achieved with structured elements made from an elastomeric plastic. A cleaning element is thereby produced which generates a brushing effect and associated high cleaning action on the tooth surface. The yielding, flexible material guarantees gentle treatment. Moreover, the flexibility of the plastic ensures that the cleaning element can penetrate into narrow spaces without cutting into the gum. The thread-like endless carrier may be made from conventional thread, twisted thread, wire, a multifile, a monofile, a tape, a wick or the like.
Appropriate selection of the material for the endless carrier and the structured elements permits the structured elements to be applied directly onto the endless carrier and be fixed thereto. In a preferred embodiment of the invention, the endless carrier is provided with a plurality of support bodies made from the elastomeric plastic which are spaced apart from one another, and which support the structured elements, preferably as a single piece, on their outer surfaces. The support body encloses sections of the endless carrier and simultaneously serves as the base and mounting for the above-mentioned structured elements, which extend radially outwardly in differing directions. The support body and the structured elements can thereby be produced in a simple manner by injection molding onto the endless carrier using a one or multiple component injection molding procedure.
Should the endless carrier have a certain transverse elasticity, as is particularly the case with a multifile or a thread, the endless carrier is compressed in the transverse direction by the high pressure with which the elastomeric plastic is injection molded. This leads to an advantageous reduction in the diameter of the endless carrier in the region of the injection molded plastic which is thereby additionally secured with respect to axial displacement in the longitudinal direction of the endless carrier. An adhesion promoter can optionally be applied to the surface of the endless carrier before the plastic is injection molded thereon.
The portions of the endless carrier located between the support bodies, spaced apart in the longitudinal direction of the endless carrier, may remain untreated. However, it is also possible to enclose these sections disposed between neighboring support bodies with the elastomeric plastic, wherein, in this event, these areas do not have structured elements.
The structured elements are preferably formed by radially projecting nubs and/or bristles and/or ribs. In addition thereto or as an alternative, the outer surface of the support body may be corrugated and/or fluted. In addition, a circumferential helical rib can be disposed on the support body.
In a further development of the invention, the support body has a round, oval or polygonal-shaped cross-section to increase the cleaning effect. Alternatively, it may also be configured as a flat tape.
An essential feature of the cleaning element according to the invention, is that the structured elements and, optionally, also the support body can be elastically deformed in the transverse direction of the endless carrier. This elastic shaping capability can be achieved through the intrinsic elasticity of the elastomeric plastic. In a further development of the invention, cavities may be formed in the plastic of the support body and/or the structured elements to improve the radial shaping capability. The cavities may be open or closed to facilitate compression of the structured elements when the cleaning device is inserted into narrow dental spaces. Moreover, the cavities may also comprise a cell structure by e.g. foaming the elastomeric plastic. The foaming may create a closed or also a permeable surface structure.
The cavities may also be used to accommodate medical care products and/or a lubricating agent and/or an abrasive agent. The care products may e.g. be tooth paste. Should the cavities be closed, they can be filled with fine hollow needles, wherein the injection holes close after filling due to the intrinsic elasticity of the material, while permitting release of the injected medium upon exertion of pressure.
In addition thereto or as an alternative, a medical care product and/or a lubricating agent and/or an abrasive agent may be applied to the outer side of the support body and/or the structured elements. Corresponding means may also be introduced into the thread-like endless carrier.
In a preferred embodiment of the invention, the structured elements are rounded at their free ends to prevent injury to the teeth and the gum, as may be caused by the conventional covering having fibers comprising cut fine bristles, since the ends thereof have relatively sharp edges. Moreover, the round ends of the structured elements facilitate the folding-over thereof when guided through narrow spaces.
In a first embodiment, the cleaning element may comprise a plurality of similar structured elements and support bodies on the endless carrier. Alternatively, structured elements and support bodies made from different materials and with differing shapes can be disposed on the endless carrier. Some support bodies may e.g. be provided with structured elements having care products, medicine or abrasive materials, with their neighboring support bodies having structured elements without such additional substances. The differences could be indicated to the user using corresponding colors.
In order to use the cleaning element as dental floss for cleaning teeth, the user must cut a section off the endless carrier and hold the ends thereof with his/her hands. This is facilitated by disposing holding means on the endless carrier at defined distances, which consist of plastic and are preferentially injection molded thereon. The user simply cuts the endless carrier behind the holding means and can then grasp the cut-off section at the holding means to facilitate cleaning of the teeth. The holding elements may be injection molded enlargements or plates to facilitate grasping of the separated section of the endless carrier.
In addition, the endless carrier may have orientation elements at defined distances, which are preferentially injection molded thereon, and which indicate where the endless carrier should be cut, both during production of the cleaning element as well as during its use.
In certain applications, it may be reasonable or desirable to connect the section separated from the endless carrier to form a continuous loop. This may be achieved by injection molding connecting elements onto the endless carrier which may be connected to each other after separating off a section, to form a continuous loop.
A dental floss is usually accommodated in a casing from which a user can pull out the desired length. The casing has a cutting device with which the user can cut off the pulled out section of the dental floss. If the cutting device is a moveable knife, the dental floss may comprise triggering means at defined distances which trigger the knife as soon as they pass a corresponding stop.
Previous applications for the cleaning element were restricted to its use as dental floss. However, in a further advantageous application, the endless carrier is subdivided into short sections and these short sections are then used in a conventional manner as bristles in a brush, in particular a tooth brush. Towards this end, the structured elements and/or the support bodies may be made from a hard or elastomeric plastic.
The above-mentioned object is achieved with respect to a method in that the structured elements are formed by injection molding a plastic, in particular an elastomeric plastic, onto a thread-like endless carrier. A support body, enclosing the endless carrier, is preferentially simultaneously injection molded and is axially secured on the carrier by the injection pressure and the resulting deformation of the endless carrier in a radially inward direction. If a two or multiple component method is used, structured elements and/or support bodies of different materials may also be applied to an endless carrier. Further features of the method may be extracted from the above description of the cleaning element.